In it, Harding adroitly chronicles the struggles of journalist and lawyer Glenn Greenwald who published the initial article about Snowden’s disclosures in TheGuardian, the liberal British newspaper, Ewen MacAskill, a veteran reporter sent by the The Guardian to check out his veracity, and Laura Poitras, the documentary filmmaker of the Iraqi-centered My Country My Country, who says she’s been detained and questioned and her possessions taken from her about forty times by agents of the Department of Homeland Security. The trio met Snowden for the first time in a Hong Kong hotel room and then helped broadcast his exposés to the world.

Harding spends time on his newspaper’s determination to publish the story despite the Conservative government’s threats and its destruction of the newspaper’s hard drives. He demonstrates how British spymasters, operating in a country without First Amendment protection or a written constitution, genuflected before Washington because Uncle Sam paid their bills, or as one cynic at Government Communications Headquarters, the British counterpart to the NSA, told Harding, “We have the brains, they have the money.”

He also describes American pressure on The Guardian’s U.S. editor, the hard-driving Janine Gibson, and her small, computer-savvy staff, not to print Snowden’s leaks. She worried lest the material in her possession be stolen before portions appeared, as they later did, in the New York Times, Washington Post and Der Spiegel. Nevertheless, she published Greenwald’s article, which opened with: “The NSA is currently collecting the telephone records of millions of U.S. customers of Verizon, one of America’s largest telecoms providers, under a top-secret court order issued in April.”

Snowden, writes Harding, is a libertarian. What’s more, he thinks he’s a “thoughtful conservative” as well who voted for Ron Paul in 2008, once admired John McCain, opposed gun control and backed the Free Tibet movement. The son of a former Coast Guard officer, Snowden joined the U.S. Army but was honorably discharged after breaking his legs in a training exercise. He then joined the CIA, quit, and for three years worked for the NSA in Switzerland, moved on to Japan, and finally joined the private contractor Booz Allen Hamilton in Hawaii, where he had the right to use unencrypted files, which much to the mortification of the U.S. also included German Chancellor Angela Merkel’s personal and official communications.

Living with his longtime girlfriend in Hawaii and earning $122,000 a year might make for most an idyllic and satisfying life, but Harding says Snowden developed a conscience when he learned what the spy agencies were up to and reached the conclusion that no one in positions of authority, either in the second Bush or Obama administrations, ever raised any questions or challenged the indiscriminate collection of data.

By the time he left Japan in 2012, Harding writes, “Snowden was a whistleblower in waiting.”

After releasing the first wave of documents and obviously fearing arrest, Snowden flew to Hong Kong, where, writes Harding, a “mysterious guardian angel” protected him, person still unknown. It was in that Hong Kong hotel room that Greenwald, Poitras and MacAskill gathered to hear his story. It’s a mystery to Harding and everyone else who has written about the case why the U.S. didn’t apprehend Snowden since it was no secret that he was registered at the Mira Hotel in his own name, used his own credit card, and wandered freely through the city.

In that hotel room, the trio “felt they were involved in a joint endeavor of high public importance, with a large degree of risk,” especially after Snowden handed them another bombshell: The top-secret Presidential Policy Directive 20, dated October 2012, in which Snowden claimed Obama had secretly ordered his national security and intelligence officers to create a listing of possible foreign targets for cyber-attacks. Snowden convinced them he could show NSA was, as Harding puts it, “tapping fiber-optic cables, intercepting telephony landing points and bugging on a global scale” and could prove everything. When she heard this Poitras said, “I almost fainted.”

By then, Snowden had become Public Enemy No. 1, and he fled Hong Kong, first to authoritarian Beijing and finally to Putin’s equally authoritarian Russia, where he remains because of U.S. pressure on countries not to accept him. Harding relates how the socialist Bolivian president Evo Mirales’ plane, en route from Moscow to La Paz, was forced to land in Britain, a clear violation of diplomatic immunity, and then Morales and his entourage were held for fifteen hours because of unsubstantiated buzz that Snowden had been aboard.

The Snowden Files is not hagiography and Harding, clearly smarting from the harsh treatment accorded his newspaper -- the The Guardian’s editor-in-chief, Alan Rusbridger, wrote a foreword to the book -- hasn’t a kind word to say about Britain’s security police. He is, however, obviously sympathetic to Snowden and to some extent the imprisoned Chelsea Manning, though far less so to Wikileaks’Julian Assange, the original mass leaker and the subject of one of Harding’s earlier books.

Nor does he believe that Snowden is anyone’s foreign agent as Republican Rep. Mike Rogers, the chairman of the House Intelligence Committee, has alleged without thus far offering any evidence. A New York Times front page story on February 9, 2014 reported “Investigators have found no evidence that Snowden’s searches were directed by a foreign power.” In his own defense, Snowden believes the White House’s campaign to criminalize his behavior and pile on felony charges is an injustice. “Speaking the truth is not a crime,” he has said. He'd like to say as much before the Congress, which may never happen.

NSA’s stated mission is to guard the country’s most secret military and computer networks, especially from Russia and China, both of whom the U.S. has charged with cyber spying. No wonder so many in Washington would love to bring Snowden home to stand trial and take the consequences, which could very well include a lengthy prison sentence rivaling the thirty-five years handed Chelsea Manning.

Harding accepts the fact that, while the U.S. and Britain have lots of enemies, he and Snowden object to targeting individuals, which “was what the spy agencies did. The problem was with strategic surveillance, the non-specific ingestion of billions of civilian communications, which Snowden laid bare.” Obviously, Snowden’s critics disagree.

All the same, what Snowden did was generate an absolutely necessary public debate about the enormous power of the central government since the post-9/11 “war on terror” and the effect it has had on privacy and civil liberties. Moreover, he arguably highlighted the tension between a secret federal agency and the American reverence for personal privacy, as enshrined in the Fourth Amendment.

So is Edward Snowden a traitor who has badly compromised national security? Is he destined to become Edward Everett Hale’s fictional army Lt. Philip Nolan, The Man Without a Country, who turned his back on his country and was sentenced to spend the remainder of his life in exile, never again allowed to set foot on American soil? Or is he a modern Daniel Ellsberg (he regularly champions Snowden) who once exposed governmental lies about Vietnam or perhaps the computer wizard recently celebrated by a group of former whistleblowers?

Meanwhile, the battle continues. Books by Glenn Greenwald and Barton Gellman of the Washington Post will soon be out. Many others will surely follow.